Solutions of vinylidene chloride polymers in a solvent containing a sulfoxy group



' polymerlzable Patented Feb. 1, 1949 amino STATES Parser sp es SOLUTIONS OF VINYLIDENE lJI-HJJRIDE POLYMERS IN A SOLVENT CONTA'EN mo A SULFOXY GROUP Ray Gide Bouts, Snyder, N. Y., assignor to E. I. du Pontde Nemours &v Company, Wilmington, Del., a corporation Delaware No Drawing. Application April 1, 194?, Serial No. 788,730

21 Claims. (or. est-soc) This invention relates to new compositions of matter and shapedarticles produced therefrom.

- More particularly, this invention relates to new compositions of matter comprising organic solvent solutions of polyvinylidene chloride. 1. e., polymerized vinylidene chloride (-CHrCClc-M and copolymers and lnterpolymers oi vinylidene chloride and to the productionoi shaped articles from said organic solvent solutions or said polymers of vinylidene chloride.

Polyvinylidene chloride and copolymers and in-- terpolymers of vinylidene chloride with other substances possess desirable physical and chemical properties such as toughness and insolubilityin and insensitivity to common solvents. However the vinylidene chloride polymers that are sumclently high melting to be useful in the formation of synthetic fibers, yarns and films, etc., are dimcult to form into these articles because, heretofore, efiective solvents have not been readily available, the polymers being insoluble in the commonly used solvents such as acetone, toluene, ethyl acetate, etc. Further, since the polymers are not sufficiently stable at temperatures above their melting points, fabrication by melt-extrusion techniques has been precluded. It has previously been known that solutions could be prepared by dissolving polyvinylidene chloride or copolymers of vinylidene chloride in certain liquid compounds taken from the class of polychlorinated aromatic hydrocarbons, aliphatic, alicyclic and alkyl-aryl ketones .or open-chain-or cyclic aliphatic ethers. However. these solvents and the solutions formed therefrom have not proved satisfactory and it has been the practice in most instances to use interpolymers having low melting points.

been adapted to ready use and the application of melt, solution orplasticizer techniques has been limited to polymers of low molecular weights and low melting points.

The most interesting vinylidene chloride polymers and copolymers (containing 95% or more by weight of vinylidene chloride) are those having molecular weight in excess of 5,000, a softening pointat or above 170 0., and stability at temperatures up to 200 c. The commercial polymers oivinylidene chloride, however, normally consist of copolymers containing 8% to 10% or Accordingly, the high melting point polymers have notaction, etc. Furthermore, copolymers of polyvinylidene chloride having relatively low vinylidene chloride content do not have form stability. For example, oriented yarns made from polymers havlng 8% to 10% -copolyn'ierizable materials retract on heating to a considerably greater extent than do yarns or nionofils made from high vinylidene chloride content polymers. Accordingly, it is desired to use the high molecular weight, high flattening polymers which have good heat stali y.

It is, therefore, an object of this invention to dissolve polyvinylidene chloride and its copolymers in which at least by weight of the polymer is vinylidene chloride in solvents which do not react with nor decompose the polymers and which may be substantially completely re= moved from structures formed from the resultant solutions, thereby permitting the ready commer .cialization or the more outstandingpolymers of vinylidene chloride.

It is another object of this invention to produce 4 solutions of polyvinylidene chloride or its copolymers in which at least 95% by weight of the polymer is vinylidene chloride in solvents which do not react with nor decompose the polymers, the solutions being suitable for the formation of filaments, yarns, films and other commercially useful articles.

It is a further object of thisinvention to produce solutions of polyvinylidene chloride or of copolymers or interpolymers oi vinylidene chloride in which at least 95% by weight is vinylidene chloride in volatile organic solvents which solutions are eminently suited for use, in the manuiacture of shaped articles such as yarns, films,

tubes, bristles, ribbons or molded articles.

It is still a further obiect of this invention to produce shaped articles and structures of polyvinylidene chloride or copolymers or interpoly- .mers oi vinylidene chloride in which at least 95% pounds containing at sulfoxy groups s=o, i; liq/ g A n' the unsatisfied sulfur valences may be satisfied least one of the following by attachment to an alkyl. alkylene or aryl group.

The alkylene groups may be in heterocyclic combination with the sulfur atom. Further, a given compound may contain more than one sultoxy group, as, for example, in 2,2-bis(ethyl sulionyl) butane. When the sulioxy group is o a [my Y 3 a' the amine portion NRR.' may be derive( from such amines as n-amylamine, ethylamine, piperidine, butylamine, dibutylamine, isobutylamine and the like. The useful solvents of this invention, accordingly. comprise straight chain and cyclic sulfoxides, suliones and suli'onamides.

In addition to compounds containing one of the above sulioxy groups, it has been found that in general amides derived irom carboxylic acids and having the iollcwina formula s-li-r and certain compounds having sulfide or ester groups are capable of dissolving vinylidene chloride polymers containing at least 95% by weight of vinylidene chloride. In reference to the additional solvents mentioned above, in those compounds containing the disubstituted carbamyl group by the group in the amide formula above, contains at least two carbon atoms and may be derived from such acids as acetic acid, butyric acid, crotonic acid, lauric acid, methoxyacetic acid, N,N-dimethyl carbamic acid, oxalic acid, adipic acid, benzoic and glycolic acid. When the acyl radical is derived from polybasic acids, all or a portion oi! the carboxyl groups may be converted to amides by reaction with any oi the secondary amines as dimethylamine, diethylamine, methylethylamine, dibutylamine, diphenylamine, or piperidine. Preferably, all the carboxylic acid groups are converted to disubstituted carbamyl groups.

This invention, of course, is not limited to carboxyiic acids, but may employ non-carboxylic acids such as the sulionic acids. As pointed out above, amides of benzene sulionic acid and ptoluene sulionic acid prepared from any of a large number of amines may be used in preparing the new compositions of matter of this invention.

Representative compounds coming within the scope oi the above formulas and suitable for use for the above-mentioned vinylidene chloride polymers include: 5 CIH|BO-CQH| Dlplienyl luliexide 'CsHsCHJBOCHaCeHI I Dlbenzyi sulioxide C Hr-C H| B0: CHr-Cfig 'letrametbyisnc suiione CHr-Oflg 80g OKs-0Q Bl Alphwmethyltetrsmethylene suiicne OKs-OH CIHISOINHCHII N-Amylbenzenesuiionsmide CHiCaHcSOzNHfhHn N-Amyi-p-toluenesuiionsmide CHICOHGSOIN(CIHH)I N ,N-Dismyl-p-toluenesulionsmids OHaCufiiSOaNHOsHI N-Ethyi-p-toluenssulionsmidc OH| i CH| H: N-(p-Toluenesuiionyhpiperidinc ciclmsolN'ncin. N-Butylohlorobenzcnesulionamide COHIISOINECHICH(CHI)I N-Isobutylcyclohexanesuiionsmide B I S -1,3-Dithiollnc OH:CON(O H N,N-Disthylsostsmide GHS(CHI)XOCON(OQHI)I N.N-Diphcnylleuramidc cmcnnsom ring.

CHiC ON 90 C. and extruded by a wet spinning process through spinnerets oi. 0.004 inch hole size into water. heated to 90 C. Coagulation is rapid and alter a bath passage of 25 inches, the yarn is wound up at the rate of 25 yards per minute on a bobbin. After washing the yarn free of excess solvents, the'yarn is dried in a circulating oven heated to 50 C. and drawn to a stretch ratio of 3:1 on a roll heated to 120 C. Before drawing. the yarn is opaque but improves in luster,

Y strength and toughness on drawing.

otherwise specified, illustrate preferred methods of preparing solutions in accordance with the principles of this invention and of employing these solutions in the manufacture oi commercially satisfactory shaped articles. The invention is not to be limited by the details set forth in the examples.

Example I Forty (40) parts of polyvinylidene chloride polymerized according to themethod of E. C. Britton et al., as described in U. 8. 2,333,633, are mixed with stirring into 60 parts of tetramethyl urea. A clear, viscous solution is formed on heating to 130 C. for fifteen minutes with stir The solution which has a viscosity of 50 pulses is dry spun into a multifilament yarn through a spinneret containing ten holes, each 0.05 mm. in diameter, into a spinning -cell such as that described in U. 8. 2,404,714 to George H. Latham. The air to the cell is heated to 150 0., circulates upward countercurrent to the filaments and exhausts at 200 C. The walls of the cell are heated to 320 C. After a nine foot travel through the cell, the yarn is wound up at a'speed of to 50 yards per minute. The filaments are drawn to a stretch ratio of 8.5:1 by passing over a driven roll heated to 135 C. This multiillament yarn which has a zero strength temperature of 170 C. under a load of 15 pounds per square inch has a dry tenacity of 2.5 grams per denier and 15% dry elongation.. The yarn is set by subjecting it to a temperature of 100 C. for fifteen minutes whileheld at the drawn length, whereupon it has only moderate retraction in boiling water when heated in the relaxed condition. The yarn has a highly desirable luster, is very insensitive to water, most organic solvents, acids and alkalies. I 1

This solution may be extruded on to a chromium plated film casting wheel heated to a suitable temperature to form a transparent film. After passing through a suitable drying medium such as a current or warm air,-the film may be stripped off the casting wheel and wound'up. The film I is highly moistureproof and durable at room temperature.

Example II Twenty (20) parts of the vinylidene chloride p lymer are dissolved in parts of N-acetyl piperidine by heating and stirring at C.

for thirty minutes. The solution is cooled to Example III Twenty (20) parts oi the vinylidene chloride polymer are heated with 80 parts of tetramethylene whom to a temperature of 140 C. After thirty minutes of stirring, a clear solution results. This solution is extruded into a coagulating bath consisting oi glycerol heated to C., through spinnerets having holes, the diameters of which are 0.003 inch. The yarn is drawn through the bath for a distance of 25 inches, whereupon it is removed by means of a vertical guide and wound up on a rotating bobbin at the rate of 25 yards per minute. The tension in the spinning bath is maintained at 0.25 gram per denier by suitably designed tension rollers. The yarn is semi-lustrous and has a dry tenacity of 2 grams per denier and an elongation of 15%.

Example IV The above-mentioned compounds are given to illustrate effective solvogenic groups, This invention is not limited to these specifically named compounds. For example, the various hydrocarbon groups, both aliphatic and aromatic, may be substituted. Eilective substituents include halogen, oxygen, sulfur, ester, hydroxyl, thiol. cyano, thiocyano and sulfoxy groups. Further. the aliphatic groups may contain unsaturated groups. In the main, these groups are inert toward the polymers. Generally, the unsubstituted, less expensive compounds are preferred since the commercial operations can be carried out smoothly with them at low cost.

Ii'the solvent hasa relatively low boiling point (less'than about 250 C.), the solution of the particular vinylidene'chloride polymer may be formed into a shaped structure, for example a yarn or film. and thesolvent removed from the shaped structure. When the solvent is relatively non-volatile and has a boiling point of about 300 C. or more, shaped articles maybe made from the solution and at least a portion of the solvent may be retained therein. as a plasticizerfor the articles. a a

The solvents of this invention are miscible in a wide range of proportions with polyvinylidene chloride and copolymers and interpolymers of vinylidene chloride and they do not appear to react with or decompose them. Many of the compounds are also miscible with (soluble-in) such non-solvent liquids for the polymeric materials as water, aqueous salt solutions, -alcohol. glycerol, etc. Solutions of vinylidene f chloride polymer in many of the compounds ofthis invention can therefore be extruded into such nonsolvent liquids to form shaped articles of the polymer, with the solvent being removed by the selective solution in the liquid coagulant. Shaped articles may also be produced by extruding the solution into an evaporative medium which evaporates the solvent. Shaped articles obtained from these solvent solutions are substantially undecomposed and chemically unchanged from the simple polymer prior to its solution. By the use of the new compositions of matter of this invention, vinylidene chloride polymers may be shaped in the form of filaments, yarns, films, tubes and like structures by apparatus generally known to the art, the detailed operating condi tions being suitably modified.

The solvents oi this invention are all capable of dissolving polyvinylidene chloride and its copolymers at temperatures below 190 C. and some solvents are capable of forming solutions at room tem erature. Many of the solvents dissolve or retain the polymer in clear solutions only at elevated temperatures, for example temperatures above 100 C. or higher, below which tempera--. tures the composition resembles a gel. In all cases when the polymer is dissolved in a solvent of the above classes, the resulting composition, while hot, has the appearance of a true solution. When cooled to room temperature, the composition generally takes on the appearance of a gel, which gel may, on standing, undergo syneresis. The heating of this gel, synersid, or mass, however, causes it to again return to solution form. Many of the solvents form solutions which gel only very slowly at room temperature and certain of the polymer solutions formed by the use of certain solvents of this invention are stable at room temperature. In the main, all compositions of this invention are substantially stable at temperatures considerably above room temperature.

Non-solvent softeners such as dibenzyl ether can also be incorporated in the solutions of this invention, these materials remaining in the subsequently formed articles to impart a softening effect. If plasticizing or softening agents are to be used with polyvinylidene chloride, it is preferable to add them in the desired amount to an already formed solution of the polymer in a low boiling solvent, for example to a solution of the polymer in tetramethyl urea. Plasticized articles can then be prepared either by extruding the solution into a coagulating bath which does not dissolve the plasticizer, or by dry spinning or casting the solution under conditions which do not cause the evaporation of the plasticizer.

At the same time, it is also characteristic that the solvents of this invention are useful, not only in connection with polyvinylidene chloride, but

also with copolymers of vinylidene chloride withother polymerizable substances such as, for example, compounds containing one or more ethylenlc linkages including vinyl and acrylic compounds as well as olefinic or diolefinic hydrocarbons such as isobutylene, butadiene, etc. They are satisfactory for use with those polymers that contain an appreciable amount of vinylidene chloride, for example polymers and coplymers that contain at least 95% by weight of vinylidene chloride. Since the introduction of other monomers generally makes for greater solubility, the solvents of this invention are usually eifective in dissolving polymers or interpolymers of vinylidene chloride which contain less than 95% or vinylidene chloride. 4

The bulk or mass polymerization process is generally used to polymerize vinylidene chloride. The monomer may also be polymerized in a, non- 8 I polymerizable solvent by the solution polymerization process. These processes are generally known to those skilled in the art and are capable of many variations. Further information concerning polymerization procedures for vinylidene chloride may be obtained from any standard textbook, such as, for example, "The Technology of Plastics and Resins, by J. Phillip Mason and Joseph F. Manning.

The solutions of vinylidene chloride polymer as disclosed herein, must be of such a concentration that their viscosity at the operating temperature is within a workable range. When it is to be employed in the spinning of yarn or the casting of film, the solution should preferably have a viscosity within the range of .25 to 500 poises. This requires a polymer having a molecular weight in excess of 0,000 to 10,000, which value constitutes the approximate lower limit of the useful range of molecular weight. Generally, solutions containing 10% to 40% by weight of polymer find ready application.

The compounds ontaining the solvogenic groups described above are capable of dissolving at least 20% to 30% by weight of the various polymers and, in many cases, are miscible in all proportions. Also, the higher boiling solvents may be used as plasticizers to the extent that they will constitute as much as 35% by weight of the plasticized polymeric material or even more if desired.

' The temperatures used in preparing the various compositions of this invention depend in part upon the boiling points and. the eifectiveness of the particular solvents. Thus, temperatures up to about 200 C. may be employed. Solutions may be prepared in an atmosphere, of inert gas and vacuum or other suitable techniques may be employed to degassify the resultant new compositions prior to their use.

Yarns and films and similar structures of polyvinylidene chloride prepared from modified or unmodified solutions can be stretched to yield oriented structures possessing a high tenacity, a desirable elongation and a good elastic recovery. The articles are not contaminated with undesirable salts and are substantially free of void spaces.

As indicated previously, these solutions are very useful for the manufacture of shaped structures such as yarns, films, molded articles, lacquers, coating compositions, etc. This is an improvement over the prior art in that the previously chloride as defined in this invention are very modifications can be made in the above described details without departing from the nature and spirit of the invention, it is to be understood that the invention is not to be limited to the details described herein except as set forth in the appended claims.

I claim:

1. As a new composition of matter, a polymer of vinylidene chloride containing in the polymer molecule at least 95% by weight of vinylidene chloride and a sulioxy compound selected from the group consisting of diphenyl suli'oxide, dibenzyl sulioxide, tetramethylene sulfone, alphamethyltetramethylene sulfone, beta-methylenetetramethylene sulfone, 2,2-bis(ethylsulfonyl) propane, 2,2-bis(ethylsulionyl) butane, N-amylbenzenesulionamide, N-amyl p toluenesulfonamide, N,N-diamyl p toluenesulionamide, N,- ethyl-p-toluenesulionamide, N,N-dibutylbenzenesulfonamide, N- (p-toluenesulfonyl) piperidine, N-

claim 2 in which the polymer is polyvinylidene r chloride.

4. A new composition or matter as defined in claim 2 in which the polymer has a molecular weight in excess of 5,000.

5. A new composition of matter as defined in claim 2 in which the solution has a viscosity within the range 25 to 500 poises.

6. The composition of claim 2 in which the solution" contains at least oi. said polymer of polyvinylidene chloride.

7. As a new composition oi. matter, a polymer of vinylidene chloride containing in the polymer molecule at least 95% by weight of vinylidene chloride dissolved in tretramethylene sulione.

8. A new composition of matter as defined in claim '7 in which the polymer is polyvinylidene chloride.

9. The composition of claim 7 in which the solution contains at least 10% of said polymer of vinylidene chloride. i

10. The composition of claim 7 in which the polymer has a molecular weight of at least 5,000.

11. The composition 01 claim 7 in which the solution has a viscosity within the range or 25 to 500 poises.

12. As a newcomposition of matter, a polymer of vinylidene chloride containing in the polymer molecule at least 95% by weight of vinylidene chloride dissolved in diphenyl sulioxide.

' 13. A new composition of matter as defined in claim 12 in which the polymer is polyvinylidene chloride. v

14. The composition of claim 12 in which the solution contains at least 10% of said polymer oi vinylidene chloride. 1

15. The composition of claim 12 in which the polymer has a molecular weight of at least 5,000.

16. The composition of claim 12 in which the solution has a viscosity within the range of 25 to 500 poises.

17. As a new composition of matter, a polymer of vinylidene chloride containing in the polymer molecule at least 95% by weight'oi' vinylidene chloride dissolved in N-N-diamyl-p-toluenesulfonamide.

18. As a composition of matter as defined in- 500 poises.

RAY CLYDE HOUTZ.

REFERENCES crrEn The following references are of recordin the file of this patent:

I UNITED STATES PATENTS Number Name Date 2,127,400 Gibbs Aug. 16,-1938 2,265,119 Coolidge Dec. 2, 1941 Houtz July 2a, 1946 Certificate of Correction Patent N 0. 2,460,579. February 1, 1949.

RAY CLYDE HOUTZ It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 5, line 5, for that portion of the compound reading CO(CH read N00(0H and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in'the Patent Ofiice.

Signed and sealed this 5th day of July, A. D. '1949.

THOMAS F. MURPHY,

Assistant Uommz'ssz'oner of Patents. 

